Signaling system



Feb. 19, 1946. F. CRABTREE ET Al.

SIGNALING SYSTEM e sheets-sheet 1 Filed May 27V, 1944 00N mozaom Feb. 19, 1946.

L. F. CRABTREE ETAL SIGNALING SYSTEM Filed May 27, 1944 6 Sheets-Sheet 2 l O3 LINE NO. DISPLAY POT NO. D ISP LAY LEONARD FA. CRABTREE MILTON L. MARKEY ATTO RNEY` Feb. 19, 1946. .F. cRABTREE ET AL SIGNALING SYSTEM 6 Sheets-Sheet 3 Filed May 27, 1944 O |2 3 6.7 8 .M |234 55T4 .89 66 6666 A@ l Cr ...J5 55 55 M/|. IU 3 Fes f f f 3 o fr 4 3 )4 m @4.4.1121-- 5v 2 4 .B ||||l|| |44- l a 4 5 VM 4 44 4 G W M 4 2 6 4 M m 4 4 4 4 O 3 :12W .-4444 ,155ML .w 4 5% .M 2 4 8 w M K 4 6 2 4 O .N --4 M. 4 4- 44x44 5 C 5 U f 7 M 5 O M M .l 4 A.. 2 8 B 4 6 4 .uw n A4. 4 44.----

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Y. mmv E TBE N NAK R ERR. 0 ,VCA 4 T N M .N I FL D Mw N wu LM Y 6 B 6 1 l Ai? 462 -403 404 412 46 BLACK sTAMP) PEN MAGNET LRED STAMP L, F. CRABTR'EE ET Ax. 2,395,168

SIGNALING SYSTEM Filed May 27, 1944 Feb. 19, 1946.

LINK |30 573, sul 574 sul 575) 515; 575) 51s;

- INVENToRs.

LEONARD F. cRATRl-:E MILTON l. MARKEY TTORNEY Feb. 19,1946.

| F. CRABTREE vE1' AL I SIGNALING SYSTEM Filed May 27, 1944 6 Sheets-Sheet 5 INVENTORS. LEONARD F. CRABTREE MILTON L. MARKEY ATTORNEY 6 Sheets-Sheet 6 Feb. 19, 1946. L F. CRABTREE Erm.

`.SIIKWLING SYSTEM Filed May 27. 1944 L INK |30 .E E E R 7 R W l 9 W 5 m 0y I 5 WOM ma M m L l l In :I l K P N .om *z .Qw. muv. A 5 OL M LLLLLLL bkk t G LFE 7 CL n um Y Al. n. B .lfwIIIIIIZ- TI 1 5 T, am \|.3M I, Il (1 1, Wm. m. a 7 l1 |l.l I| .llll ril I l I l l l I l I l I l l l l I I I Il m ITQIJ. I l l l l l 7 im H G m H El U, T 5 7 3 n 9. o .w s) Psw n n w m m m Patented Feb. 19, 1946 SIGNALING SYSTEM Leonard F. Crabtree, La Grange, Ill., and Milton L. Markey, Columbus, Ohio, assignors to Automatic Electric Laboratories, Inc., Chicago, Ill., a corporation of Delaware Application May 27, 1944., Serial No. 537,700

46 Claims.

The present invention relates in general to 'sig- .maling systems, and more Vparticularly tothe use of such systems for producing displays ci information 'at :remote points.

It is .an object of the invention to provide an improved system wherein a common control center can select display panels situated `in different zones and cause Apanel to display different items of information. Another object of the invention is the provision of a system o'f this character, wherein the information displayed upon 'the panel Ain any zone is based upon information received. "in the control center from that zone. Still another object is to provide a system of the .character described, wherein a plurality of items of information. each selected from a larger group of items, may he displayed concurrently upon any one 'of said panels.

A further object of the invention is to provide, at Vthe control center 'in such a system, a plu- "ralityo'f stations each capable of controlling the display panels inthe 'manner indicated; another obe'ct is to provide facilities common to said stations whereby different ones o'f said stations may control different :ones of 'said panels at the same time.

ne feature of the invention resides in the improved circuit arrangement by means of which the common 'facilities are taken into use by any station at the control center. In accordance with another feature of the invention, the `facilities employed to produce a display upon any panel may 'be released, and the display consequently wiped out, either under control of the station which "caused the display to be vproduced or under control of means 'at the display panel itself. In accordance with still another feature, a 'register operated differently to indicate in which of these ways the facilities have 'been released.

'In accordance with another feature oi the invention the information selected to be displayed is also displayed at the control center together with an indieation of which remote panel has been selected to carry the ldisplay 'of `that 'information'; inacco'rdance with a 'further feature, the display 'at the V'control center is-produced first, and 'the :information thereafter is 'displayed upon the selected remote panel only in response to a further manual operation than performed Yat the control center.

In accordance with another feature ol the invention, arrangements are provided for registering the 'time at whioh'a display vupon any panel is initiated and 'the `time at which the display thereaiter is wiped out.

In accordance with still another .feature of the invention, impulses are transmitted from a station at the control center to select the desired remote panel and to select the information to be displayed thereon. In accordance with a further feature, a permanent record of the selecting impulses is made, together with a permanent record of the time at which the selected display is actually produced at the remote panel, and the time at which the display is wiped out, the latter record being made in such a way as to indicate whether the display was wiped out from the control center or from the remote panel.

Another feature ofthe invention resides in the provision of .a telephone system to supplement the display system, and inthe provision of certain equipment common to both systems.

Other objects and features of the invention will appear from the following description taken in connection with the drawings in which:

liig` l 'is a schematic diagram of the system,

Figs. 2A and A2B show sections of a paper tape marked by the recorder employed in the system, and,

Figs. 3 to '7, when assembled as shown in Fig. 8, comprise a detailed circuit diagram of the systern. More particularly, Fig. 3 shows one of the stations at the control center and the line equipment individual thereto, as well as a pair of link seizure relays common to all such control stations and the lamp display panel individual to one link; Figs, 4, 5, 6 and 7 together show one of the .1inks; and Fig. 7 also shows the lamp display panel and other equipment situated in each of two remotezones.

Referring to Fig, 1, the invention will be described as being applied to an arrangement for supervising and guiding the work done in a large foundry 2130 from Aa centralized control room ll. Located in twelve .diierent zones in the foundry are twelve Lcasting lines numbered as shown. Each casting line is assumed .to havesixteen individual furnaces .or heating pots vsuch `as .|05 in which metal is brought to the proper molten state to be poured into flashs for casting the .desired objects. Because it is important for the metal to be at the proper temperature not only when it 'is poured but also at certain stages in the process of preparing it to he poured, each pot is connected toits :own recording pyrometer, such as 1MB, which iis mounted upon a common pyrometer panel fil-'2D in the control room. Stationed :in the control room are expert Aattendants "who, 'guided by lthe pyrometers, decide how the different pots should be treated, and instruct the foundry workers accordingly.

The instructions are given through the medium of lamp panels situated at the head of each casting line. The workers in any line thus may be directed to carry out any one of a group of predetermined operations (such as raising the pot temperature, lowering the pot temperature, pouring the metal, etc.) by displaying upon the panel at the head of that casting line a number or a legend indicative of the desired operation, and, at the same time, displaying a number indicative of the pot to which the instruction pertains.

The arrangements for controlling the lamp panels now will be outlined briefly. In the control room are ve identical control stations |50, |60, |70, |80 and |90, each having an individual line circuit such as |5| over which access may be had to either of two links 30 or |40. The transitory operation of a key at any station will cause link |30 or link |40, whichever happens to be idle at the moment, to be seized, and will make that link temporarily inaccessible to the other four stations. At the same time a lamp identifying the seized link will be lighted at each station. This lets the operator know which link is under his control and also serves to keep the other attendants informed as to the availability or unavailability of links for their own use.

At the seizing station a dial or other impulse sender no will be operated to transmit to the link three numbers, one indicative of a particular castling line, another indicative of a particular pot in that line, and a third indicative of a particular operation to be performed with respect to that pot. Each of the rst two numbers may consist of either one digit or two digits.

As each number is received the link causes that number to be registered upon a display panel in the control room, by intermittently flashing an appropriate lamp therein. It also selects certain lamps in the display panel at the head of the particular casting line whose number was dialled, but the lighting of these lamps is withheld pending the further operation of a key at the control station. When the operator thereafter actuates the latter key the lamps thus selected will light, displaying the pot number and the operation lnumber which were dialled. The actuation of this key causes the link also to operate a horn or other audible signal at the head of the casting line in question, in order to call the attention of the foundry workers to the display. At the same time it changes the condition of the lighted lamps in the control room from flashing to steady, to

`inform the operator there that the equipment has functioned properly to bring up the display in the foundry.

The display in the foundry and in the control room will persist until the link is released. A foundry worker may bring about such release by operating"a release key associated with the panel in which the display appears, whereupon the consequent wiping out of the display in the control room, accompanied by the extinguishment of the link seizure lamps at the five control stations, will signify to the operator in the control room the foundry workers acknowledgment of the instructions transmitted. Alternatively, the link may be released by operating a release key at the control station; as a matter of fact the latter key is capable of releasing the link at any time after its seizure, and hence may also be employed, for example, to restore the link to normal before the operation has been performed to bring in a display in the foundry, if the operator discovers that he has made a mistake in dialling.

Recording equipment under the control of the link makes a permanent record of the digits dialled, the time at which the display was initiated, and the time at which the link was released. It also indicates upon the record whether the release was initiated in the foundry or in the control room.

It will be clear that the provision of two links makes it possible for directions to be given to the workers in any two of the casting lines at the same time. Should an attempt be made, however, to so control one of the links as to cause a display to appear at any casting line at a time when the other link already is in use for a display at the same line, the attempt will be unsuccessful. 'I'his prevents any confusion from arising in the directions given to the foundry workers in that line.

With the aid of the circuits disclosed in Figs. 3 to '7, inclusive, the mode of operation now will be described more in detail. Referring to Fig. 3, the equipment shown to the left of the vertical dot-and-dash line is individual to station |50 in the control room, and it will be appreciated that identical equipment for each of the four remaining control stations is connected in multiple to the conductors 303 to 3|5, inclusive. Of the latter conductors, 3|| to 3|5 extend to link |30, shown in detail in Figs. 4 to 7, inclusive, while the conductors 3| I to 3| 5 extend in corresponding fashion to link |40, as indicated. Relays 350 and 355 are common to all five control stations, the former relay being individual to link |30 and the latter being individual to link |40, as will be made clearer presently.

For purposes of explanation, it will be assumed that an operator in the control room wishes to transmit an instruction from station |50 to the foundry. To do so, he momentarily operates key 320 to its start position, whereupon, if link |30 is idle, relay 330 will operate over the following circuit: positive battery, contact 32 I, lower winding of relay 330, conductor 303, contact 35|, and negative battery. Upon operating, relay 330 closes contacts 334, 335 and 336 to prepare circuits which extend over conductors 3| I, 3|2 and 3|3 to link 30. At contact 33| it completes a locking circuit for its upper winding, While at contact 332 it completes an energizing circuit for relay 350. Contact 333 opens the circuit to the lower winding of slow-'to-operate relay 340.

Relay 350, upon operating, opens contact 35| to disconnect negative battery from common conductor 308, thereby to characterize link |30 as busy. This has no effect upon relay 330 which remains operated over its upper winding, but it prevents the corresponding relays for the four other control stations from being energized in the event that the start operation should now be performed at any of the latter stations.

It will be appreciated that, had link 30 been thus characterized as busy at the time key 320 was operated, relay 330 could not have operated over its lower winding as described, due to the absence of negative battery on common conductor 308. Under these circumstances if link |40 were idle, slowtooperate relay 340 would operate after a delay, over the following circuit: positive battery, contacts 32| and 333, lower winding of relay 340, common conductor 3 l0, contact 350, and negative battery. Thereupon contoets 3M, 315 and @It would be closed to prepare circuits to link lill. Contact SII would complete a locking circuit for the upper winding or relay 340 While contact 342 would complete an obvious circuit for relay i355. The latter relay upon operating disconnects negative battery 'from comLa mon conductor till thereby to characterize link No as busy in the same way that relay 35o functions tocharacteriae link ist as busy.

lt will be clear that whenever both links are in use, relays 55D and 355 both will be operated, making it impossible for 'any other control sta tion to gain access to the links. ri both links are idle at the time the start operation is per formed at one or the stations, the lower windings of relays 33t and 34u in the line equipment in dividual to that station will be energized in parallel, but, being faster to operate, relay 33!) will pull up and open the circuit to relay 3M at contact 333 before the latter relay can operate.

In the present instance it `will be assumed that link 13B is idle- After the operation of relays 33u and son as described, nothing further will occur until key 32|) is restored to 'its normali or diah position. Upon vsuch restoration lowing circuit is completed: positive battery, con tact 32?, dial Contact l321i, contact 3351, conductor 3l l, winding of relay 4to, .and negative battery, Relay son operates over t "is circuit at contact 402 energiz'es a control elle the recorder Alle. et the same time it energlues slow-torelease relay M15 over the 'followu ing circuit: positive battery, `resting armature 4c,operated armature sul, winding of relay llos and negative battery. .Relay m5 operates and contact M15 completes a circuit extending over contact Mt and the 'upper winding of relay whereupon the latter relay operates, closing con-V tact 4GB to initiate the operation of the motor 461 in the recorder Mit.

The recorder is assumed to be of `the well known type wherein the motor stl by means of a sprocket drive moves a paper 'tape 211i (see Figs. 2A and 2B) under 'a pen trol magnet M33. This causes the pen to trace upon the tape a line 2u?! (Fig, 2A) whose lateral position at any point lalong the tapes length in dlcates whether magnet Alle was energized or deenergized at that point. The recorder also irrcludes a pair or clock-controlled time stamping mechanisms of well known character; one is ac tuated by the erlergization of magnet #.62 to stamp the date and time in black ink on the tape above tuated by lenercitation of 'magnet M2 to stamp the date 'and time in red ink below the line 2&2-,

Returning now to the operation this at contact 4M completes an obvious `circuit forrelay 4in vouch. in turn opens contact all. Contact 40B prepares a circuit to relay 425 while contacting completes the following circuit: pos-i` tive battery, resting armature 434, contacts lloc and M5, winding of slow-to-release relay all, and negative battery. 'Relay M2 operates vover this circuit and at contact 413 completes an obvious circuit for slow-to-release relay M4. r'line latter relay upon operating opens the circuit for relay M2 at contact sie, causing relay lf2 to restore afterla delay; this in turn opens Contact dill, causing relay M4 to 'restore after a :further ydelay. whereupon at contact M5 relay als is recaer gized. Relays 4t2 and 4 I4 continue to interact in the manner described, whereby relay M4 alter nately operates and releases in cyclic fashion.

which is adapted to be moved transversely or the tape by the pen cons i f the line 292, while the other is acl the operators at other stations in Each time relay M4 operates it closes contacts 16 and 411, thereby to energize relays 42u and MI. Accordingly the latter relays operate and reelase in unison with relay 4M. Relay 42| performs no useiul function at this time, but relay B2B, at contact 422, periodically connects alternating current to common conductor 315, causing the link seizure lamp 32o at station 58 (and the cor-responding lamps at the remaining four sta-V tions) to dicken This indicates to the operator at station i513 that `link ISG is prepared to receive impuls-es from his dial, while it serves to inform the 'control room that link |30 is in use.

The operator now will dial the number of the casting lineat the head of which is the display panel he wishes to control. For identification purposes the twelve lines are assigned the fol lowing numbers:

ln the present instance it will be assumed that the operator dials the number "03 which is indicative of the last one of the twelve casting lines. Since this vis a two digit number, two manipulations of the dial are required. Upon dialling 0 the impulso Contact 325 momentarily interrupts the circuit for theA relay Mil) ten times in suc cession, and upon thereafter dialling 3 the circuit is interrupted three further times in succession,

When contact 325 opens for the lirst time, relay dilo restores to normal, causing contact 45| to complete the following circuit: positive battery, resting armatures 481i and 40|, contact M18, winding of the slow-to-release relay 425, resting armature 431, conductor 551, rotary switch magnet 5l5, and negative battery. Relay 425 operates, opening contact 426, While magnet 5I5 operates to prepare the reverse drive switch 5H] for its rst step. When Contact 325 recloses to terminate the first impulse, relay Mill reoperates and at armature MH interrupts the above-traced oircuti for relay 425 and magnet 5i5. The consequent deenergization of 'magnet 5 i5 causes wipers 5H and 5l2 of rotary switch 515 to advance to Contact I of their respective banks.

'In similar fashion relay Mill responds to the subsequent nine impulses in the rst train and repeats them to magnet 5l5, causing the switch wipers to be advanced step by step; concurrently, at contact 432, relay Mill repeats the incoming impulses to the pen control magnet 403', causing them to be recorded upon the tape driven by motor MB1.

Upon each impulse, contact Mil momentarily interrupts the circuit for slow-to-release relay 40.5, but these interruptions are too brief to peri'nit the relay to restore. Slow-to-release relay 425 likewise remains operated throughout reception of the train of impulses, but at the end of the train it restores to normal due to the prolonged opening of its circuit at armature MII. Accordingly contact 425 thereupon closes, connecting positive battery over resting armature 484, contacts 426 and 533 to wiper 512. ln the present oase wiper 512 will be standing upon contact lo in its associated bank (ten impulses having been transmitted from the dial at control station leo) and, since no circuit is connected to this particular bank contact, the connection of positive battery to wiper 512 will be of no effect.

Upon the rst interruption of its circuit in the second impulse train,

0, SIG' and H0 in parallel, and negative battery. Accordingly, these three relays operate. It will be appreciated that if the number of any other casting line had position as to operate another set of relays identical to 5|0, SIG and 7|0, there being twelve such sets, of which only the rst and last set are shown.

Link |40 (illustrated in part in Fig. 5) has twelve similar sets of relays which are adapted to be operated selectively over wiper |4|2 in the same way the twelve sets in link |30 are selected and operated over wiper 5|2. Corresponding sets been preceded by the upon operating to sound the buzzer 365,

by opening Contact 466. Hearing the buzzer |50 would know that ordinarily whereupon the him; this will occur of link |40, relay |4|0 restores to normal. Thereupon, contact |4|3 completes the above-traced circuit for relays SH), GIU and 7|0, and at the same time interrupts the circuit for relay 430, causing the buzzer 355 to cease sounding and causing relay 445 to release. The latter relay opens contact 441 to place relay 400 again under control of the dial contact 325 and at contact 446 reoperates relay 465 to cause the motor 461 to resume operation.

In the present instance it will be assumed that link |40 is idle, or, if in use, is being used to produce a display before some casting line other than line 03. Accordingly relay |4|0 is at normal, and, upon the release of relay 425 after the 1| 0, traced locking circuit.

At contacts the control room.l This lamp ashes in accordance with the interruptions of its circuit by contact 422.

The operator now will dial the number of some one of the pots in the casting line. For identification purposes the sixteen pots in each line are assigned the following numbers:

It will Vbe assumed that number 9.

armature 438, resting armature 443, conductor 562, wiper 522 in position 9, conductor 518, Winding of relay 620, and

tact 335, while at contact 363 lt prepares a reits circuit by contact 484; it causes the inter-f lease circuit for link |30. Contact 36| connects action between relays 4|2 and 4|4-to cease, and positive battery to conductor 361 to maintain rerelay 44V permits relays 420 and 42| to restore lay 350 operated, and at the same time interto normal. Relay 6|0, upon releasing, Opens the rupts the holding circuit for relay 336. The lat- 5 circuit for relay 435 at contact SI2, While at ter relay accordingly restores to normal, but this contact 6|3 at once more conditions link |46 to 463 are locked up via contact 45|, conductor 428, i0 lay l'l opens the circuit for relay 455. Relays l At the casting line 03, a foundry worker, hear- Upon returning to normal, relay 435 completes ing the horn 160, will take notice of the display the following circuit: positive battery, operated establishes an obvious circuit for the windings of position 25, where it halts.

relays 410 and 413 in parallel. Relay 410 operates 25 Relay 440 upon returning to normal completes more quickly than slow-to-operate relay 413, but the following circuit: positive battery, operated when the latter pulls up it interrupts the circuit armature 484, conductor 566, wiper 52| in posifor relay 410 at contact 414, causing relay 410 to tion 9, interrupter contact 526 of the magnet restore. This momentary energization of relay 525, conductor 553, contact 44|, conductor 559, 41|) causes Contact 41| to deliver an impulse to 30 magnet 525, and negative battery. Magnet 525 the time stamp magnet 412, which thereupon operates self-interruptedly in this circuit, hence records upon the tape in red ink the time at switch 520 is advanced step-by-step until wiper which release of the link was initiated. At con- 52| reaches position 25, where the switch halts.

tact 415 the following circuit is completed posi- When switches 5|0 and 520 both nave reached tive battery, contacts 456 and 415, upper wind- 35 their twenty-fifth position, relay 415 restores to 111g 0f relay 430. and negative battery. normal, since now the circuit for its upper Wind- Relay 480 opeiates, opening contact 483 and ing is open at wiper 5| and the circuit for its closing contact 486 to maintain relay 36D operlower winding is open at Wiper 52|. Accordingly ated independently of contact 454. Contact 484 contact 411 opens, causing relays 480, 4|0 and completes the following circuit: positive battery, 40 413 to release. Allof the relays and rotary Operated armature 434, Conductor 536, Wiper 5H switches in the link now occupy their normal positions, it being understood in the case of switch winding of relay 415, and negative battery; relay 530 that positions 6, t2, '8 and 25 are au home positions. The link seizure lamps, such as 326,

ones of said relays upon release; and horn 166 h sil n h e f 't t operated armature 484, conductor 566, wiper 53| 50 Ctg? ze jldttzpemnb o l s clrcult a Upon the restoration of relay 480 to normal,

cuit for relay 350 which thereupon also returns to normal. Accordingly contact 35| reconnects negative battery to common conductor 368, which tact at." and conductor 57.0 from the-pos1tlve has the effect of making link |36 again accessible pOtentlal encounteled by wiper 53|..0I1 15S ESSO to all Ve of the control stations. Seizure and control thereof in the manner described above therefore now may be repeated.

As an alternative to the mode of release set countered, however, when wiper 53| reaches con- 60 over its u er windin alone.

I'he oplation of cntact 484 opens the cir- 65 pose a' two-Way release key 390 1S provlded at cuits for relays 405 M2 445 450 453 458 62o the station. In order to release link |30, the key 6m, am', no and 120' causing these to restore to will be moved downward, closing contacts 39| normaL Relay 445 opens Contact 441, Where and 332. The latter contact will have no effect upon relay 400 also restores to normal; contact in the Present instance' but at 005mm? 39| the the slow-to-release relay 495 is opened, and hence contact 39|, contact 363, conductor 3|4, windings relay 465 is momentarily reoperated. This at 0f relilly 457 and 450 in parallel, and negative contact 466 briey reenergizes motor 461, which battery. Relay 460 Operates more quickly than thereupon advances the tape a short distance. slow-to-operate relay 457, but when relay 457 AWhen relay 4|2 releases due to the opening of 75 pulls up it causes relay 460 to 4release by opening acentos contact. 45.8.. The: momentary encre-ization or relay 4.6 i causes; contact 46|; to. deliver an impulse to time stamp magnet 452 which thereupon. records, in. black. inleg, the timeV at; which the. release was initiated` At contact 459. the: following. circuit. ist completed: positive; battery, contacts 319A. and yconrluctor 3114,. contact 459-, upper winding: of relay 48o, and negative battery'. Relay 48o operates4 as;- hereinbeioreexplained:brings. about the restorationA to. normal. of switches -l-il, 523- and. 530- and. the releasev of relay-s 4351 40d-, 41.2 414 42|), 412i,5 435 440;, 4415-, 4-50, 4E3,.41t3, 415-, 6211;. 6.120 Gill', 'I t3 and. l2-iii., Relay 4.51 remains. operated untilkey 35.0- and relays 4,15- a-nd 4.3.5- all return to, normal, tlien it too releases.` When key 3.90.1-,` switch 530,. and rela-ys 4&5` and 41.5- a-ll have;

returned. to normal,i rela-y 48d releases, causing relays;` 440 330- a-nd' 353i to. restoreasl previously described. This places the link in condition to be seized by anycontrol. station and used` once moreto-prodncea display before any desired casting line.

2A. showsI a. sectionof tape ail-i.- containing the. record produced by recorder Milt in response to the; dialling ot the digits 0391,. as described, followed by the operation of the display keyand. then, after an interval, by the operation of the releasefkey atv station. ld.. Each received. impulse appears, as,- atoothextendingl downwardly from the-base line. 20.2. traced by the pen, and it will bef. Seli-evidenti thatY the first group contains ten impulses.' (corresponding to. the. digit 0-), the second; group containsth-ree impulses, and so on. Botinlegendstollowing. the last recorded impulse are. madeby the time stampi-ng mechanism control-ledby magnet. 4.3.2-, the. rst; legend indicating the time. atw-liich-.the display was initiated, while the` second indicates the; time. ot release.. The tact that. the. time.- of release is recorded in the same color (black) and on the. same side ot line. 232 asthe time of display, indicatesthat the link wasE released under control of station |54.. If the link. is releasedrunder control. of the key associated With-.thedisplay panel, in the. foundry, therecord willibeidentical tothatshown. in. Fig. 2A` except. that` the second legend. will be. stamped by magnet 43.2,. andI hence, will be inr a. different. color andrpos-itioned. below the line. 33.2, as. shown ini 2B.

I-t willl be observed that. release key 33t. may alsa-bev employed to release` the,v lin-k at any time. before a display has. been produced by it. in tno foundry; Assume,` for instance, that. the link. has j ustheen seized, and that the operator, without yetfliaying. dialled.. any digits, wishes to release. Relaya 33.3,. 3.50, 493;-, 4ii5, dill, 46.5 are energized, while-relays: 4t2, 4.4.4, 42.3. and 4M are: operating. interm-itten-tlyl as described. Upon operation. of. key 39A)y totrelease, link. i353, the following circuit is. completed: positive battery, contacts 3.92-, and 336, conductor 3l3, windings of relays 45d., 43.6.! and. 4.6.3. in. parallel', and negati-vebattery. Relay 460. operates, and then atter a brief: interval restores to. normal upon the opening of Contact 4Ii4.- when. the slow-to-operate relay 4:33 pulls up. Tcl-1e;- momentarily closing oi. contact 464 causes. time. stamp magnet 4:52 to. recordl the time.. The operation of contactl 4.64. connects positive. battery to1 relay 463. which energizes but produces no` useful eiect: at thisi time..

Relay 4550-,A upon opera-tion,y at,y contact.4.5.-Il con. pietostno-following-` locking circuit: positivebat- Gerts. resting, armature 484 conductor 42.8, con-- tact. 45.15 windings.- of. rela-ys; 4.5.0., 463- and; 4.68,.- inparellelg. and nega-.tive battery.. Contact` 453.-.1ocksv u-p relay 420.', which at. contact 422 changes the; condition ed lamp 32.6. from flashing.' to steady.. Contact 45.4v completes an. obvious. circuit over contact'` 48:31, conductor 342: and contact; 3.35. operating relay 361i.. Relay 366 locks. itself up at Contact` 3612, whil'eat contact Siti-I i-t-locksup relay 351i and opens. the.` circuit for. relay 3:30.. The latter. relayA upon restoring tof normal opens. contact 334 and. consequently relay 439i also. releases. This: initiates. the; release of: relay' @55' by openingits circuit at contacteer..

Meanwhile, returning; to a consideration of the. operation of relay contact 33; connaletes:A the following circuit.: positive battery, contacts. Sal. and 363i, conductor 3114, the windings of relays; dit? andllllin parallelr and negative battery. Relay 4&8 operates. and then, after. a. brieil interval, restores. to'. normal dire to. the. opening of. its' cir:- cuit at. contact. 4&8 when slow-to-operate. relay 4.527 pulls. up. The momentary' operation. of contact; llzl causes; timestamp magnet. 431' aga-in to. rer-:ordi the: time. Upon operati-ng. relay 4&1; also completes. a circuitV frompositi've. battery4 on conductor 31I=4 over contactliilz to energize; relay 4815);.

Relay 48o operates, andr it the. release or relay 435 has; not. yet taken place',.lo.cks-iufrt over contact 485 to positive. battery on contact4011f. 4.83.' isl opened; and contact. 4M; closed tcmaintain relay 36.01 operated independently of contact 454-.. The. operation of Contact 484: opens anotlfieri point. the circuit of. relay 46.5,. and opens. the circuit'l for relays 412,. 43), 453:, and 46.8. When relay 4t2 releases dueto the opening of contact 4.84,. causes the. interaation` between relays 4t2 and 44.41 to. cease, and. relay 414- permits relays: 42o and 42-1- to: restorextonormali Relay 4.5.1- releases responsive. to the opening of its circuit. at. contact 35i-I when4 release key 390 is.; restored. t@ normal. When key 3.9i]` and relay 445. both are at normal, relay 434: releases, causingrelays 4lll,.35.3. and 334Y also to-release as; pre-A viously described, Link i3!!- having thus been restored completely to normal, now is once morev accessible to' a-ll-` control stations..

InI the event.- that release key 396i is operated to restorelin-k. L30: to norma-l after part or. all of the digits. have been' transmitted. toit, but before; key 320? hasv been operated toits Dis-- play positionetherelease will: take-place in sub-` stantially the same way as just described, the; only difference being due tothe fact that. when` release: key 39o is operated. one` or more.- of the switches 5M), 530` andi. 53|]` will be olii-normal, one or more; of the relays 435-, 4.4i! and 445 will. beoperated,r ande certain.- of the. relays` in- Figs. 6 and. '7 will have; beeny selected and operated. All of these latter devices willi bereturned toz normal under control ofrela-y 483 in the mannerhereinmv before explained.

Associated with the display facilities described above is al direct line telephone.- system by means of. which. any static-n in; the control room may communicate withany casting line. inthe foundry. This permits the. instructions givenr via the lampv panels tobe supplementedby Verbal instructionsv whenever necessary, and it enables. the foundry workers to inform operatorsA in the control room. of any circumstances arising. which may demand` special attention,

Eachstation in the control room has a set of twelve selections keys numbered. to correspond to the. twelve casting. lines. If the operator at station |50 sliouldwisln` to talk toy aworker at line 03, for example, he will lift the handset 395 from ts cradle and momentarily operate: selection. key

Contact 398; Contact 396 bridges the telephoneset across conductors 395 and 395, thereby causing battery feed relay 439 to operate in the usual way, but the consequent closing of contacts 49| and 492 has no effect. Key 398 connects positive battery to conductor 394, operating relay 495. Relay 495 in turn connects alternating current over contact 496 and conductor 554 to horn 160 at casting line 03. Hearing the horn sound, a worker will answer the call by means of the usual telephone instrument, shown schematically at 190. Both the calling station and the called station are supplied with talking current via the windings oi' battery feed relay 499, which will, of course, return to normal when both stations hang up.

On the initiation of a call from the foundry, the bridging of the telephone equipment at the calling station (for example, 190) across conductors 55| and 552 causes battery feed relay 490 to operate. Assuming that link is not at the time in use for display purposes, the following circuit will be completed upon operation of relay 490: positive battery, contact 391 of the hook-switch at station |50, the corresponding hook-switch contacts 391a, 391i), 391e and 391el at the other four control stations, conductor 30|, contacts 49|, 4H and 4|5, winding of relay M2, and negative battery. Relay 4|2 energizes and operates relay 4I4, whereupon relays 4|2 and 4|4 interact in the manner previously described. Upon each operation, relay 4|4 closes contacts 4|6 and 4|1, causing relays 420 and 42| to operate and release in unison with relay 4|4. Con.. tact 422 connects alternating current periodically to conductor 3|5, causing lamp 326 and the corze,

responding lamps at the four remaining control stations to nickel". The following circuit also is completed: positive battery, contacts 391, 391a, 39117, 391e, 3914i, conductor 30| interrupter contact 424, contact 492 and gong 366. Accordingly the gong sounds intermittently in accordance with the interruptions of its circuit by contact 424.

The call may be answered at any one of the control stations. Assuming that an operator, hearing gong 39S, answers the call at station |50, it will be observed that contact 391 opens the circuit for the gong when the handset 395 is lifted, thereby causing it to be silenced; contact 391 also opens the circuit for relay M2, whereupon the interaction between relays 4|2 and 4|4 ceases, and relays 420 and 42| restore to normal. The calling and called stations now are in direction connection, their respective telephone instruments being supplied with talking current over the windings of battery feed relay 490.

If, in the above case, link |39 had been in use for display purposes at the time the call was instituted from the foundry, the operation would have been the same as described except that, due to contact 4H being open, the functioning of relays 4i2, 4|4, 420 and 42| would not have been initiated by the closing of contact 49| nor halted by the opening of contact 391, These four relays would be functioning prior to the closing of cont-act 49|, (due to a circuit for relay 4|2 which extends over contacts 484 and 499) and they would continue so to function after contact 391 opened. The energization of relay 490 would, however, by closing contact 492 initiate the intermittent operation of gong 366 as described, while Contact 391 of the hook-switch at station |59 would silence the gong when handset 395 was lifted.

Havingv fully described the invention, what We consider new and desire to protect by Letters Patent will be set forth in the appended claims.

What is claimed is: l. In a signaling system, a primary station, a

' plurality of secondary stations, a display panel at each of said stations, switching equipment under the control of said primary station operated to select any desired one of said secondary stations and to condition the panel at the selected secondary station to display any particular one of a plurality of different items of information, check-back means in said equipment operated to cause the panel at said primary station to display an identification of the selected secondary station and the selected item of information, and means thereafter operated responsive to a manual operation performed at the primary station for causing said conditioned panel to display said selected item of information,

2. In a signaling system as claimed in claim l, means at said selected secondary station operated at times to wipe out the display at that station.

3. In a signaling system as claimed in claim 1, means whereby the display at the selected secondary station can be wiped out under the control of either the primary station or the selected secondary station.

4. In a signaling system, a primary station, a plurality of secondary stations, a display panel at each of said stations, means under the control of said primary station operated to register the identity of any desired one of said secondary stations, other means under the control of said primary station operated to register any desired one of a plurality of different items of information, means controlled by said first registering means for conditioning the panel at said one secondary station to produce a display, other means controlled by said two registering means to cause the panel at said primary station to display both the identity of said one secondary station and said one item of information, and means at said primary statio-n operated at will after said display thereat for causing said conditioned panel to display said registered item of information.

5. In combination with a plurality of groups of devices, each group being situated in a different zone and each device having a particular variable characteristic, a remote station, means at said station controlled by said devices to register the variations in said characteristic of each device, and means at said station controlled in accordance with the registered variations in said characteristic of any particular device for selecting the zone in which that device is located and causing a plurality of items of information to be displayed in that zone, one of said items being an identification of said particular device and another of said items varying in accordance with the registered characteristic of said particular device.

6. In a signaling system, a. plurality of primary stations, a plurality of secondary stations, a plurality of groups of devices at each of said secondary stations, switching equipment common to all of said stations, means at each primary station for at times seizing said equipment and operating it to select any desired one of said secondary stations and also to select any desired device in each of said groups at the selected secondary station, and means in said equipment operated responsive to a single manual operation thereafter performed at the primary station by which said equipment was seized for operating all of the selected devices at the selected secondary station without operating any of said devices at any.V other secondary station.

7. In a signaling system, a primary station, a plurality of secondary stations, a plurality of groups of devices at eachv of saidV secondary stations, switching equipment under the control of said primary station operated to select any desired one of said secondary stations and also to select any desired. device in each of said groups at the selected secondary station, means at said primary station controlled by said equipment to 'station operated toV select any desired onel of said called stations and also to select any desired device. in each of said groups at the selected called station, means in said equipment for transmitting to said calling station an identification of the selected called station and an identification of the selected device in each ofr said groups, and means in said equipment operated responsive to a single manual operation thereafter performedv at said calling station for operating al1 of the selected devices at the selected called station.

9. In a signaling system, a plurality of calling stations, a plurality ofY called stations, a plurality of' groupsl of devices at each of said called stations, switching equipment. common to all of said stations, means at each calling station for at times seizing said equipment. and operating it to select any desired one of said called stations and also to select any desired device in each of said groups at the selected called station, means in said equipment for transmitting to said calling station an identification ofthe selected called station and an identi-cation of the selected device in each of said groups, and means in said equipment operated responsive to a single manual operation thereafter performed at said. calling stationl for operating alll of the selected devices at the selected called station.

10. In a signaling system, a plurality of calling stations, a plurality of called stations, a plurality of groups of devices at each of said called stations, a pair of links each common to all of said stations, means at each calling station for at times seizing an idle one of said links and operating it to select any desired one of said called stations and also to select any desired device in each of said groups at the selected called station, and means in the seized link operated' responsive to a single manual operation thereafter performed at` the seizing station for operating allof the selected devices at' the selected station `without operating any other of said devices either at the selected station or at any other called station.

1l. In a signaling system as claimed in claim l0, means in each link eiective, responsive to iat link being operated to select any one of said called stations, totemporarily so disable the other link that said other link cannot operate any of the devices at` thel called station selected by said first link but can operate any of the devices at any of the, other called stations.

l2. In a signaling system as-claimed in claim 10, means in each link effective, responsive to thatr link being operated to selectany one of said called stations, to temporarily` sov disable the other link that said other link cannot operate any of the devices at the called station selected by said first link but can operatev any of the devices at any of the other called stations, and a signal operated by said other link in the event that it is seized and operated to select the same called station which has been selected by said iirst link While. said other link is thus disabled.

13; In a signaling system, a plurality of calling stations, a plurality of called stations, a plurality of groups of devices atv each of said called stations, a pair ci links each common to all of said stations, means at each calling station for at times. seizing an idle one of said links, means controlled by the seized link for producing at the seizing station a. visible indication of which link has been seized, means at the seizing station for operating the seized` link toselect any desired one of said called stations and also to select any de.- sired device in each of said groups at the selected called station, and means in` the seized link op:- erated responsive to a single manual operation thereafter performed at the seizing station for operating all of the selected devices at the selected station without operating any other of said devices eithenat the selected station or at any other called station..

14. In a signaling system,` a calling station, a plurality oi called stations, means at said calling station for transmitting a first group of impulses indicative of any one of said called stations and a second group Of impulsesindicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means controlled by said registering means to display at said calling station the identity of said one called station and of said one item of information, display means at each of' said called stations, and meansfcontrolled by said registering meansy for causing the display means at said one called station to display the item of information indicated by the registered impulses of said second group. i

l5. In a signaling system, a plurality of calling stations, a plurality of called stations, equipment common to said stations, means at each of said calling stations for at times seizing said equipment and transmitting thereto a rst group of impulses indicative of any desired one of said called stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means in said equipment for registering said impulses, means controlled by said registering means to display at said calling station the identity of said one called station and of said one item of information, dispiay means at each of said called stations, and means controlled by said registering means for causing the display means at said one called station to display the item of information indicated by the registered impulses of said second group,

16. In a signaling system; a calling station; a plurality or called stations; means at said calling station for transmitting a rst group of impulses indicative of any one of said called stations, a second group of impulses 4indicative of any one of a plurality of predetermined items oi information, and a third group of impulses indicative of any one ofl certain other predetermined items of information; meansfor receiving and registering said impulses; display means at each of said called stations; and means controlled by said registering means for causing the display means at said one called station to display the two items of information indicated by the registered impulses of said second and third groups.

17. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting three groups of impulses corresponding respectively to three variable items of information, means controlled by said impulses for registering said three items of information, means controlled by said registering means for displaying said three items of information at said calling station, and other means controlled by said registering means for selecting a called station in dependence upon one of said items of information and displaying the remaining two items at the selected called station.

18. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting a first group of impulses indicative of any one of said called stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means controlled by said registering means to display said one item of information at said calling station, other means controlled by said registering means for conditioning said one called station to wipe out said display, and means at said one called station effective only if operated after said one station has been thus conditioned for wiping out said display.

19. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting a rst group of impulses indicative of any one of said called stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means controlled by said registering means to display said one item of information at said calling station, other means controlled by said registering means for conditioning said one called station to Wipe out said display, an audible signal at said one called station operated under control of said registering means when that station has been thus conditioned, and means at said one called station effective only if operated after said one station has been thus conditioned for wiping out said display.

20. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting a first group of impulses indicative of any one of said called stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means controlled by said registering means to display at said calling station the identity of said one called station and of said one item of information, display means at each of said called stations, means controlled by said registering means for causing the display means at said one called station to display the item of information indicated by the registered impulses of said second group, and means at said one called station thereafter operated to wipe out the display -at said one called station.

21. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting a first group of impulses indicative of any one of said called stations and asecond group of impulses indicative of any one of a plurality of predetermined tems O f information, means for receiving and registering said impulses, means controlled by said registering means to display at said calling station the identity of said one called station and of said one item of information, display means at each of said called stations, means controlled by said registering means for causing the display means at said one called station to display the item of information indicated by the registered impulses of said second group, and means at said one called station thereafter operated to wipe out the display at said calling station.

22. In a signaling system, a calling station, a plurality of called stations, means at said calling station for transmitting a first group of impulses indicative of any one of said called stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means controlled by said registering means to display at said calling station the identity of said one called station and of Said one item of information, display means at each of said called stations, means controlled by said registeri ing means for causing the display means at said one called station to display the item of information indicated by the registered impulses of said second group, and means at said one called station thereafter operated to Wipe out both the display at said calling station and the display at said one called station.

23. In a signaling system; a calling station; a plurality of called stations; means at said calling station for transmitting a first group of impulses indicative of any one of said called stations, a second group of impulses indicative of any one of a plurality of predetermined items of information, and a third group of impulses indicative of any one of certain other predetermined items of information; means for receiving and registering said impulses; means controlled by said registering means for display at said calling station the two items of information indicated by the registered improvements of said second and third groups; other means controlled by said registering means in accordance with the registered impulses of said first group to condition said one called station to wipe out said display, and means at said one called station effective only if operated after said one station has been thus conditioned for wiping out said display.

24. In a, signaling system, a calling station, a plurality of called stations, a display panel at each of said stations, means under the control of said calling station operated to register the identity of any desired one of said called stations, other means under the control of said calling station operated to register any desired one of a plurality of different items of information, means controlled by said first registering means for conditioning the panel at said one called station to produce a display, other means controlled by said two registering means to cause the panel at said calling station to display both the identity of said one called station and said one item of information, means at said calling station operated at will after said display thereat for causing said conditioned panel to display said registered item of information, means controlled by said registration of the identity of said one called station for conditioning said one called station to wipe out the display at that station, and means thereafter operated responsive only to a manual operation performed at the-conditioned called station for wiping out the display at that station.

In.; a signalingV system,.a cal1ing-station,. a plurality of called` stations, a. display panel. at each of; said stations, means under. the control of said calling station operatedA to. register the identity of. any desired one oi said, called. stations, other means under the control; of saidcalling, stationv operated. tov register any desired one of a plurality of diiierent items of information, means controlled by said iirst. registering` means for conditioning' the panel at. said onecalled'- sta.- tion toproducaa display, other'means controlled by said two registering means to cause the panel at said calling station to display both the identity of said one called station and saidv one item of information, means att said calling` station operated at will after said display thereat for. causing said conditoned' panel to; display said.` registered item of information, means controlled by saidregistrationofthe identity of said onercalled station for conditioning saidone called station towipe out the display at` that station, means thereafteroperated responsive only to a manual operation. performed at, the conditioned called station-for wiping out the. display at that station, and alternative meansv operated responsive only to a manual operation performed at. said. calling station for wiping out the, display at said one called station.

26'. In a signaling system, a primary station, a plurality of secondary stations, a plurality of groups of` devices at each ot said secondary stations, switching equipment under the control oi said primary station operated to select any desired one of said secondary stations and' also to select any desired device in each of said groups at the selected secondary station, means at. said primary station controlled by said: equipment to display the identity of' the selected secondary station and alsoI the identity of the selected device in` each of said groups, means in said equipmentoperated responsive toy a. singlemanua-l operation performed a-t said primary. station for; operating alloi the selected devices at the selected secondary station, and means then operated under control of the selected, secondary station for wipingv out said display.

27. In a signaling system, a plurality of primary stations, a plurality of secondaryA stations, a plurality of groups of devices at each of said secondary stations, switchingequipment common .to all of said stations, means at. each primary station for at times seizing said` equipmentand operating it to. select any desired one of said secondary stations and` also to selectlany desired device. in each of said groups` at the selected sec.- ondary station, means controlled by the selecting of said one secondary station for conditioning that station to release said` switching, equipment, means in said equipment operated responsive to a single manual operation performed at the pri.- mary station by which said equipment was seized for operating all oiv the selected devices at the selected secondary station without operating any of said devices at. any other secondary station, and means dependent upon said conditioning means for thereafter releasing said switching equipment under the control of said one second'n ary station.

28. In a switching system, a plurality of pri,- mary stations, a plurality of secondary stations, a, plurality ci' units of switching, equipment common to said primary stations, means operated responsive to an operation performed at any one of said primary stations thereupon to seize an idle one of units, means controlled by the seized unit for producing at said one primary station a visibie;l` indication. of which unit; has been seized", meansvtlieyseized unit controlled by said one primarystationto select any oneo: said secondary stations and to condition. that, station, to release. said` unit.,y andl means at the selected. 'secondary sation, effective only ii operated after it has ibeen thus conditioned,4 for releasingv saidunit and consequently wiping4 out said indication.

29;. In a4 signaling system, a primary station, a plurality of secondary stations, switching: equipment operated under the control of said; primary, station to select` any desired one of said secondary stations and to display at the selected secondary station any one of a plurality of pre,- determined--itemso iniormation, means whereby saiddisplay can be wiped out at will under. the control either of; the; primary station or the se.- lected seconda-ry station, and registering means operated differently in dependence; upon whether said display is wiped; out under the control. of said; primary station or under the-control of the selected secondary sta-tion.

3.0.A In a signaling system, a calling station, a plurality of called. stations. means at said calling station fory transmitting arst; group of impulses indicative of any one of said called stations and a second group or impulses. indicative of any one of a plurality of predetermined items or information, means for receiving and registering said impulses, means, controlled by said registering means to display saidV onefitem ofinformation at saidy calling station, other means controlled by said registering` means for conditioning; saidone called station, to wipe out said` display,means at said; one called', station effective only if operated aftersaid one stationhas. been thus. conditioned lorv wipingy out. said display, alternative means for wiping out said display under the control oi said calling station, and registering means operated diiierently in dependence uponwhether said da play is wiped out, by operation` oi said means at said one calledstation or under the control of said calling station..

3l.. In a. signaling: system, a primary station, anpluralityoisecondary stations, switching equipment4 operated; undertne control of said primary station to select. any desired oneof said secondary stations andto display at-the selected. secondary station. any one of a plurality of predetermined items.. of. information, means whereby said dis.- play canv be wiped out, at. will under the control either of, the primary station or the selected secondary-station, means operated to register the time` atv which said display is wiped out if it is wiped, outunder. the control .of said primary station, and other means. operated tor register the time at` which; said display is wiped out if. it is wiped out under the control of said selected secondary station,

3.2. In; a signaling systerm a calling station, a plurality of called stations, means at said calling station for transmitting a. first group of impulses indicative of. any one osaid` calledY stations and a second group of impulses indicative of any one of a plurality of predetermined items of information, means for receiving and registering said impulses, means vcontrolled by said registering means to` display said one item of information at said calling station, other means controlled by said registering means for conditioning said one calledy station to wipe out said display, means at said one. called station effective only if Voperated after said. one station has been thus conditioned for wiping out, said display, alternative means for wiping out said display under the control of said calling station, means operated to register the time one called station, and other means operated to register the time at which said display is wiped out if it is wiped out under the control of said calling station.

33. In a signaling system, a calling station, a plurality of called stations, a display panel at each of said called stations, switching equipment operated under the control of said calling station for selecting any desired one of said called stations and conditioning the panel at that staparticular one of a plurality of information, means opera manual operation performed at the calling station for causing said conditioned panel to display the selected item of information, means thereafter operated for wiping out said display, and means controlled by said last two means for registering the time at which each of said last two means is operated.

34. In a signaling system, as claimed in claim 33, wherein said display can the control of either said calling station or the selected called station, means whereby said time registering means indicates the station under control of which said display is wiped out.

35. In a signaling system, means for transmitting a plurality of digits in succession, a pair of registers, means for causing one of said registers to register the first digit of said succession, and means controlled by said one register for causing the same register second digit of said succession registered is of a certain value and for causing the other of said registers to register said second digit if the first digit registered is of a different value.

36. In a signaling system, means for transmitting a plurality of digits in succession, a plurality of registers', means for causing one of said registers to register' the first digit of said succession, means controlled by said one register if the first digit registered is to cause the same register also second digit of said succession second one of said registers to register a digit subsequent to said second digit, said last means controlled by said one register to cause said second register to register said second digit if the first digit registered is of a different Value, means controlled by said second register if the first digit registered by it is of a predetermined value to register the and to cause a to cause said second register also to register the if the first digit of a certain Value f digit following the first digit registered by said second register and to cause a third one of said registers to register a digit subsequent to the second digit registered by said second register, said last means controlled by said second register to cause said third register to register the next digit following the first digit registered by said second register if the first digit registered by said second register is of a value different than said predetermined value.Y

37. In a signaling system, means for transmitting a plurality of digits in succession, a plurality of registers, means whereby one of said registers at times registers only the first digit of said succession and at other-times registers both the first digit and the second digit of said succession, means whereby a second one of said registers at times registers only the iirst digit following the last digit registered by said rst register and at other times registers the next two digits following the last digit registered by said first register, and means whereby a third one of said registers registers at least one digit following the last digit registered by said second register.

38. In a signaling system, means operated at diiferent times and eifective at each of said times to transmit a plurality of digits in succession, a register, and means whereby said register at times registers only the second digit of said succession, at other times registers only the third digit of said successio and at still other times registers both the second and third digits of said succession.

39. In a signaling system, means operated at different times and effective at each of said times cession, at other times registers only the fourth digit of said succession, and at still other times registers only the fifth digit of said succession.

operated responsive to the operation of said relay for making said link busy, thereby to prevent ariother of said relays from operating in the event that'a corresponding manual operation should be performed at any other of said stations, a connection completed from said one station to said link by said relay upon its operation, a calling device at said one station operated to transmit impulses over said connection to operate said link directively, means individual to said one station thereafter controlled by said link to complete a different connection from said one station to said link and to cause said relay for that station to interrupt said first connection, and means controlled over said diierent connection from said one station for releasing said link.

41. In a switching system, a plurality of links, a plurality of control stations, each station having individual equipment including a relay for each of said links, means effective responsive to a manual operation performed at any one of said stations for thereupon operating the relay in that stations individual equipment which corresponds to an idle one of said links, means individual to said one link operated responsive to the operation of said relay for making said one link busy, thereby to prevent another of the relays corresponding to said one link from operating in the event that a corresponding manual operation should be performed at any other of said stations, a connection completed from said one station to said one link by said operated relay, a calling device operated to transmit irnpulses over said connection to operate said one link directively, tion thereafter one link.

42. In a switching system, a plurality of constations each having a fast operating relay and a slower operating relay, two units of switching equipment each common to all of said stations, meansat each of said stations for at times simultaneously energizing both the fast relay and the slower relay individual to that station and at other times energizing the slower relay alone, means controlled by the fast relay, upon operation, for preventing the operation of its associated slower relay, means controlled by the operation of the said fast relay for seizing a particular one of said units, and means controlled by the operation of said slower relay for seizing the other of said units.

43. In a switching system, a plurality of control stations each having a fast operating relay and a slower operating relay, two units of switching equipment each common to all of said stations, means individual to one of said units effective to maintain circuits prepared to all of said fast relays whenever said one unit is idle, means individual to the other of said units effectiveto maintain circuits prepared to all of said slower relays whenever said other unit is idle, means at each of said stations at times operated for simultaneously completing such circuits as are, at each of said times, thus prepared to the fast relay and the slower relay individual to that station, means thereupon controlled by the fast relay if it operates for seizing said one unit and making same busy, means controlled by said slower relay if it operates for seizing said other unit and making same busy, and a contact on each fast relay effective whenever such relay operates to disable the slower relay individual to the same station as that fast relay, thereby to prevent the fast relay and the slower relay individual to the same station from being operated concurrently.

44. In a switching system, a plurality of units of switching apparatus, a plurality of control stations, each station having individual equipment including a plurality of relays corresponding respectively to said units, means individual to each of said units maintaining circuits prepared to all of the relays corresponding to that unit Whenever said unit is idle, means 'at each of said control stations at times operated for simultaneously completing all of the circuits which are thus prepared to relays in that stations individual equipment, means whereby no more than one of the relays in the equipment individual to any particular station may operate responsive' to the operation of said last means at that station, and means controlled by each relay which is operated responsive to such completion of its prepared circuit for thereupon causing the circuits for the other relays corresponding to the same unit as the operated relay to be disabled by the said means individual to that unit.

45. In a telephone system, two groups of substations, a line common to said substations over which speech may be transmitted from any one of the substations to any other, means at each substation of one group for selectively signaling any substation of the other group, an interrupter, means operated at random intervals for causing said interrupter to operate, means responsive to the initiation of a call at any substation of said other group for initiating the operation of said interrupter if it is not already in operation, a signal common to the substations of said one group operated intermittently by said interrupter responsive to the operation of said last means, means responsive to the answering of said call at any substation of said one groupfor at times terminating the operation both of said interrupter and of said signal, said last means eiective at other times responsive to the answering of said call at any of said substations of said one group to terminate the operation of said signal without terminating the operation of said interrupter.

46. In a telephone system, two groups of substations, a line common to said substations over which speech may be transmitted from any one of the substations to any other, means at each substation` of one group for selectively signaling any substation of the other group, an interrupter, means responsive to the initiation of a call at any substation of said other group for initiating the operation of said interrupter, a signal common to the substations of said one group thereupon operated intermittently by said interrupter, and means responsive to the answering of said call at any substation of said one group for terminating the operation of said interrupter and said signal.

LEONARD F. CRABTREE. MILTON L. MARKEY. 

